A variety of methods exist for installing a fiber optic cable to protect the cable against vandalism and inadvertent excavation. The most commonly used, most efficient and least costly installation method is to directly bury the cable using a cable plow. The standard installation practice involves putting the cable into the ground inside a protective duct or directly placing the cable into the ground without any protection. After burying the cable, a warning tape, in the form of a plastic ribbon or the like, is buried approximately two feet above the fiber optic cable. The warning tape carries indica identifying the communications cable owner.
The warning tape provides some protection to the buried fiber optic cable by alerting an excavating contractor that a buried communications cable lies in the vicinity of the tape and that great care should be taken while excavating. The warning tape is color-coded to identify the type of buried conveyance. For example, the color orange identifies communications cables. Unfortunately, such warning tapes only convey a passive warning message to an excavating contractor. If a contractor does not see the warning tape, or worse, chooses to ignore it, the contractor's digging equipment can damage the fiber optic cable. It is not unusual for a contractor to see a warning tape only after striking the fiber optic cable. Even if the contractor does not sever the cable, the contractor may expose the cable sheath by simply striking the cable, thereby, allowing the sheath to suffer corrosion to the point of destruction. Unfortunately, many excavating contractors, unless they actually sever the cable, will simply stop their digging once they have struck the cable. Rather than alert the cable owner, most contractors will cover the cable with dirt. Simply covering the struck cable with dirt may damage the fibers because of the movement of the nearby earth.
Thus, there is a need for a warning system to alert owners of other conveyances, such as gas and water lines, electrical and telecommunications cables (including fiber optic cables), of the existence and location of digging activity near their conveyances.